Active plasmonics: Controlling signals in Au/Ga waveguide using nanoscale structural transformations

We have developed a concept for active plasmonics that exploits nanoscale structural transformations which is supported by rigorous numerical analysis. We show that surface plasmon-polariton signals in a metal-on-dielectric waveguide, containing a gallium section a few microns long, can be effectively controlled by switching the structural phase of gallium. The switching may be achieved by either changing the waveguide temperature or by external optical excitation. The signal modulation depth could exceed 80% and switching times are expected to be in the picosecond–microsecond time scale.